The present embodiments relate to ultrasound transducers. In particular, the present embodiments relate to a reconfigurable transducer array.
One-dimensional transducers are used to scan a plane with electronic steering. For scanning a volume, a two-dimensional transducer may be used. However, the number of beamforming channels greatly increases for scanning with a two-dimensional transducer. Many ultrasound imaging systems do not have sufficient channels. An alternative is a mechanically rotated one-dimensional transducer (i.e., a wobbler). However, the mechanical motion may be insufficiently rapid for real-time volume scanning.
A multi-dimensional transducer array may be used with electronic switching to both provide for volume scanning and a fewer number of required beamformer channels. U.S. Pat. No. 6,676,602 describes such embodiments. For example, an electronically rotated array is an array of elements where the aperture used during scanning is electronically controlled. Switches connect different elements to different beamformer channels, allowing rotation of the aperture for sequential scanning. For example, a one-dimensional aperture is rotated electronically on the face of a two-dimensional transducer array. By controlling the configuration of the switches, the one-dimensional array may be oriented to any rotational angle. Within a given aperture, the defined one-dimensional array may steer scan lines. For volume scanning, the volume is sampled by collecting a series of azimuth-spaced beam groups at each rotation angle.
The switching to allow beamformation in real-time volume scanning may require high performance switches. From an electronic perspective, an aperture comprised of an ordered or periodic cell structure is desirable because the periodic cell structure allows macro elements to be wired up to edge traces using the fewest number of in-series switches, relaxing the “on” resistance (Ron) requirements for the switches.
Fitting a one-dimensional aperture on a multi-dimensional array may result in imaging artifacts. Beamforming problems can arise from “pixelation” errors incurred while mapping an angled 1D array onto a periodic 2D grid. Jogs in the elements concentrate energy into localized field side lobes that degrade contrast resolution.